Shulou(Shulou.com)06/02 Report--

This article will explain in detail how to write scripts in awk language. The editor thinks it is very practical, so I share it for you as a reference. I hope you can get something after reading this article.

Much like writing a shell script, the awk script begins with the following line:

#! / path/to/awk/utility-f

For example, on my system, the awk tool is installed in the / user/bin/awk directory, so my awk script starts with the following:

#! / usr/bin/awk-f

The above line is explained as follows:

#!, called Shebang, indicates which interpreter to use to execute commands in the script

/ usr/bin/awk, the interpreter

-f, the interpreter option, used to specify the program file to be read

Having said that, let's delve deeper into some executable awk scripts, starting with the following simple example. Create a new file using your favorite editor, like this:

$vi script.awk

Then paste the following code into the file:

#! / usr/bin/awk-fBEGIN {printf "% s\ n", "Writing my first awk executable script!"}

Save the file and exit, and then execute the following command to make the script executable:

$chmod + x script.awk

Then, execute it:

$. / script.awk

Sample output:

Writing my first awk executable script!

A strict programmer must ask, "where are the comments?" Yes, you can include comments in the awk script. It is a good programming habit to write comments in your code.

It helps other programmers to read your code and understand the functions of each part of the program file or script.

So, you can add comments to the script as follows:

#! / usr/bin/awk-f # this is an example of how to write comments in awk # use the special mode BEGIN to output a sentence BEGIN {printf "% s\ n", "Writing my first awk executable script!"}

Next, let's look at an example of reading a file. We want to find a user named aaronkilik from the account file / etc/passwd, and then print the user name, the user's ID, and the user's GID as follows:

Here is the contents of our script file, named second.awk.

#! / usr/bin/awk-f # uses the BEGIN specified character to set the FS built-in variable BEGIN {FS= ":"} # search for user name aaronkilik and output account details / aaronkilik/ {print "Username:", $1, "User ID:", $3, "User GID:", $4}

Save the file and exit, make the script executable, and then execute it as follows:

$chmod + x second.awk$. / second.awk / etc/passwd

Sample output:

Username: aaronkilik User ID: 1000 User GID: 1000

In the following * example, we will use the do while statement to print the numbers 0-10:

Here is the contents of our script file, named do.awk.

#! / usr/bin/awk-f # printing from 0-10 using a do while statement # do while statement BEGIN {# initialize a counter xroom0 do {print x; xbirthday 1;} while (x

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